1. Field of the Invention
This invention relates to a process and apparatus for weaving and deweaving a fabric tape so the individual warp strands may be space dyed and wound onto separate packages for subsequent use. Deweaving the tape is an essential process when space dyeing of textile yarns is carried out via the weave-de-weave process, since the tapes themselves cannot be used as a unit for further processing.
2. Description of the Prior Art
U.S. Pat. No. 3,605,225 describes in detail a weaving process which is commonly referred to as "weave-de-weave." Weft is inserted by a needle on a narrow width needle loom and knitted in a chain stitch along one side of a tape fabric including a plurality of warp threads in order that the weft can subsequently be removed after treatment of the fabric, e.g., by coloring, and the fabric unravelled to provide a yarn with intermittent coloring or splotches which is then used as pile yarn in carpets.
As the weft is removed, the individual warp yarns from the tape are separated out and wound on single one-end packages.
Typically, the yarn used for the weft filling is either nylon or polyester of a size substantially smaller than the warp yarn through which it is woven. For purposes of economy, the weft yarn must be reclaimed for repetitive use and with each re-use, the coat of the weft per pound of carpet yarn produced is decreased. However, there are serious drawbacks in re-using the weft yarn. Owing to its fine denier and to repeated subjection to both heat (during dyeing) and stress (during weaving and deweaving), the efficiency of the latter operations decrease with each re-use.
One problem associated with weft removal in the "weave-de-weave" process, therefore, is breakage of the weft thread or the presence of a knot or tangle in the weft thread as it is deweaved. This problem is compounded by the method of weft collection in which the use of a conventional ring traveler take-up is involved, which inserts variable twist in the weft end, consequently increasing the incidence of breakage and snarls in re-use of the weft. If the weft breaks or tangles, the deweaving process must stop. Broken ends must be rethreaded and repaired, and yarn tensions readjusted, all of which gives rise to considerable process inefficiency and additionally requires operator attention.
Knots and tangles, as well as breakage, of the warp threads in the process is also a problem because of the simultaneous winding of a large number of parallel yarns onto separate packages. If a knot, tangle, or breakage of a warp thread occurs, the individual warp threads cannot be properly separated, and the entire process must stop.
The loom speed in the conventional weave-de-weave process is also limited to about 1000-1200 picks per minute. Each pick, or weft insertion, can be spaced only about 1 inch from the adjacent picks, a distance limited because the movement of warp per pick is all the loom gearing allows. If the gearing limitation is removed, the warp advance per pick is still limited by the fact that the weft is wrapped around the selvage knitting needle and cannot easily be pulled through. Since the weft is fragile for economic reasons, e.g., due to its continued removal and reuse, this further limits the speed of warp production.
Further, the weft can only be withdrawn from the fabric in a reverse operation to its insertion, so that the tape must at some point in the process be reversed end for end. The tape produced is narrow (21/2 - 3 inches) and this gives rise to problems in keeping the tape free from folds. Lastly, even with due care the weft often breaks causing the deweaving process to stop, since the weft must be pulled out.
The weave-de-weave system described herein resolves some or all of these difficulties. The advantages of our method and apparatus over the prior art include the following:
(1) Wider tapes may be made on the loom since the weft insertion system employed is not the needle arm knitting needle type which can only be used over a few inches;
(2) Wider tapes mean less chance of folds in processing;
(3) While one can have wider tapes in dyeing, the tapes can be split down to any size for winding back to packages;
(4) The tapes do not need reversing and will deweave in either direction;
(5) The deweaving does not require a continuous weft. Weft breaks do not stop the deweaving process;
(6) There is no limitation on pick spacing imposed by the loom; and
(7) The system allows a continuous unwinding of weft from the supply package. Accordingly, the present invention provides a weave-de-weave process and apparatus characterized by increased speed and operating efficiency.